Current guidelines recommend stopping clopidogrel 5 to 10 days prior to colonoscopic polypectomy. However, interruption of clopidogrel therapy in patients with coronary artery disease puts them at risk of serious acute ischaemic events. Recent studies have suggested that clopidogrel can be continued as post-polypectomy bleeding (PPB) rates have been similar to those in the general population not on antithrombotic therapy. This meta-analysis of five observational studies assessed the risk of colonoscopic PPB in patients on continued clopidogrel therapy (n= 574) vs. controls (n= 6169).
The pooled relative risk ratio (RR) for PPB on continued clopidogrel therapy was 2.54 (95% CI 1.68 to 3.84, p<0.00001). For immediate PPB there was a non-significant pooled RR of 1.76 (0.90 to 3.46, p=0.10), and delayed PPB there was a statistically significant pooled RR of 4.66 (2.37 to 9.17, p<0.00001). None ofthe studies included reported a fatality.
The researchers highlight several limitations to their analysis:
• Inability to control for covariates of PPB including concomitant medication use, duration of clopidogrel therapy and other patient-related risk factors and prior PPB.
• Only five observational studies met inclusion criteria for this meta-analysis, which limits patient numbers, and therefore limits the study power to detect statistically significant findings.
• Inability to account for concomitant aspirin attributing to the risk of PPB.
• It is unclear whether specific procedure-related factors may have increased the risk of PPB.
• Inability to assess cardiovascular events among patients in whom clopidogrel therapy was stopped.
Despite these limitations, they suggest that the findings may have implications for clinical practice, as the rate of delayed PPB in patients taking clopidogrel was 2.65%, which is similar to population-based estimates of PPB risk in patients not on antithrombotic therapy, but higher than rates reported in previous studies that advocated continuing clopidogrel for polypectomy. In addition, the case fatality rate for stent thrombosis has been reported to be as high as 45% with cessation of antithrombotic agents as the strongest risk factor, whilst PPB, which is not usually life threatening, can be controlled with minimally invasive strategies. The researchers recommend that gastroenterologists weigh the risk of bleeding against that of re-infarction or stent thrombosis among patients on clopidogrel undergoing colonoscopy, and consider deferring elective colonoscopy and polypectomy until it is considered safe to interrupt clopidogrel therapy.